Fuse device



R. D. NELSON ET AL FUSE DEVICE Oct. 12, 1943.

Filed June 4, 1942 3 Sheets-Sheet l Oct. 12, 1943- R. D. NELSON ET ALFUSE DEVICE Filed June 4, 1942 3 Sheets-Sheet 2 5 R W WW m M w n M m w1943- R. D. NELSON ET AL 2,331,343

FUSE DEVICE Filed June 4, 1942 3 Sheets-Sheet 3 INVENTORS fan/4w .0 MZJU/V Patented Oct. 12, 1943 FUSE DEVICE Rolland D. Nelson and Edwin A.Link. South Milwaukee, Win, assignors to Line Material Company, SouthMilwaukee, Win, a corporation of Delaware Application June 4, 1942,Serial No. 445,748

Claims.

This invention relates to fuse devices. Objects of this invention are toprovide a fuse device which employs a fuse tube open at both ends andwhich has a headed fuse link so arranged that the head of the fuse linkcloses one end of the fuse tube, and in which the head of the fuselink-is adapted to be blown directly away from the end of the fuse tubein the event of a violent evolution of gas upon rupture of the fuse linkso that the fuse tube will be vented at both ends.

Further objects are to provide an expulsion fuse device in which a fusetube is provided which is open atboth ends and in which a fuse link ispositioned within the fuse tube and is provided with a head normallyclosing one end of the fuse tube, and in which stationary contacts areelectrically connected under normal conditions by means of the fuselink, and in which provision is made for the free travel of the head ofthe fuse link away from the end of the fuse tube without engaging theadjacent stationary contact so that even under violent overloadconditions no damage will be caused the stationary contact by theviolent projection of the head of the fuse link outwardly away from theend of the fuse'tube, and to provide a construction having thecharacteristics enumerated above in which the head of the fuse link hasgood and positive electrical contact with the adjacent electricallyconducting portion of the fuse device.

-A further specific object of this invention is to provide an expulsionfuse device in which the fuse tube is open at both ends, one end beingclosed by the'head of the fuse link and the head of the fuse link beinggripped in such a manner that under light overloads the head of the fuselink will not be blown oif and the action of the fuse tube will be thatof a fuse tube open at one end only to thereby assist in the speedyclearing of the circuit inside the fuse tube, the construction beingsuch that under heavy overloads the head of the fuse link is blown fromthe fuse tube to thereby provide venting of the fuse tube at both ends,the device therefore having both the characteristics of an expulsionfuse tube open at one end only for light overloads and vented atbothends for heavy overloads, whereby the safe rupturing capacity of theapparatus is materially increased.

Further objects are to provide a fuse construction in which upper andlower stationary terminals are provided, the upper stationary terminalbeing provided with a pair of outwardly and downwardly flaring resilientcontact arms which are adapted to directly engage the head of a headedfuse link extending through the fuse tube and normally electricallyconnecting the stationary terminals, the lower portion of the structurebeing provided with means under the control of the fuse link forreleasing the fuse tube upon rupture of the fuse link and allowing thefuse tube to drop downwardly and outwardly to inoperative position.

Further objects are to provide a fuse tube construction in which thefuse tube is mounted between upper and lower stationary terminals and isprovided with a. fuse link having a head at its upper end, the upperterminal including a latching means for normally latching the tube incircuit closing position and a pair of downwardly divergent spring armswhich are so arranged that they normally directly engage opposite sidesof the head of the fuse link and are adapted to be spread apart when thehead of the fuse link is projected outwardly upon heavy overloads, theconstruction providing a. free passage for the head of the fuse linkwithout damage to any portion of the upper stationary terminal.

Embodiments of the invention are shown in the accompanying drawings, inwhich:

Figure 1 is a side elevation, partly broken away and partly in section,showing one form of the invention.

Figure 2 is a. view looking down on the top of the structure shown inFigure 1 with a portion sectioned off.

Figure 3 is a sectional view on the line 33 of Figure 1.

Figure 4 is a view partly in section showing the upper portion of afurther form of the invention.

Figure 5 is a view partly in section looking down on the structure shownin Figure 4.

Referring to the form of the invention shown in Figures 1 through 3, itwill be seen that the device comprises an elongated insulator I whichmay be suitably supported as shown and which is provided with upper andlower contacts. The lower contact comprises a pair of spaced hook likemembers 2 which normally receive the trunnions 3 of a fuse extractingand releasing lever 4. This lever 4 is provided with a thumb nut 5 whichclamps the flexible leader 6 of the fuse tube in place. The lever 4 ispivoted'between the bifurcated ears of an arm I rigid with the lowerportion of the fuse tube.

It is preferable to provide a web like member 8 integral with the lever4, such web like memher having a curved portion, as shown in dottedlines. which prevents inadvertent detachment of the trunnions 3 from thehook like members 2 until the fuse tube is rocked to its lowermostposition. In its lowermost position the fuse tube may be lifted from thehooks 2 by means of a switch stick engaging in the hook like portion 9of the web 8.

If desired, the web 8 may be provided with curved. laterally extendingflanges as shown in dotted lines and indicated by the referencecharacter ID to assist in the positioning of the device within the looklike member 2. The lever 4 is normally held in place by the fuse linkand upon rupture of the fuse link, the lever 4 rocks downwardly andextracts any remaining portion of the fuse link and also lowers the fusetube so that its upper end is unhooked from the upper stationaryterminal and the tube may then rock outwardly and downwardly toinoperative position.

The upper terminal may comprise a strap like member I I which mayencircle the upper reduced end o'f the insulator I and which is heldclamped in place by means of the bolt l2. The ends of the strap likemember I I are inturned and the looped portion of resilient arms I3 maybe clamped in place by means of a bolt I4. The bolt I4 also passesthrough the lower end of a connector I5 and through the rear portion I6of a pair of relatively fiat spring contact arms I! so that the fiatresilient arms l1 and the round resilient arms I3, as well as theconnector l5, are securely bolted to the strap like member II.

The arms I! extend outwardly and their upper edges are drawn towardseach other so as to provide a pair of downwardly slanting contactmembers H which are adapted to engage the button head I8 of the fuselink, as shown most clearly in Figure 3. The outer ends of the flat armsH are outwardly flared to facilitate guiding of the upper end of thefuse tube and the button head of the fuse link into place when the fusetube is rocked into operative position.

The fuse tube I 3 is provided with an upper terminal member 20 which hasa pair of outwardly projecting pins 2| which engage beneath the springarms l3. These spring arms l3 are provided with downwardly depressedportions I3 which act as latching means to secure the pins 2| in placewhen the device is rocked into operative position. The arms I3 continueoutwardly and diverge upwardly and outwardly to also assist in theguiding action of the upper end of the fuse tube when the fuse tube isrocked into operative position. The upper contact 20 of the fuse tube isprovided with a manipulating eyelet portion 22 which is adapted to beengaged by a switch stick so that the tube may be rocked into positionand rocked out of position by means of the switch stick as required.

It is to be noted. particularly from an examination of Figure 3. thatthe marginal edges of the button head I8 of the fuse link are engaged bythe downwardly slanting portion ll of the contact spring arms I! andthus the button head is held firmly in electrical contact with thesearms and also in firm electrical contact with the upper face of thereduced portion 23 of the upper contact 20 of the fuse tube. In additionto this, the spring arms I3, which constitute latching arms, also havefirm electrical contact with the pins 2|.

When the fuse link blows under light overloads, the action is that of anexpulsion fuse as the button head If! is held in place. However, underheavy overloads the gas pressure within the fuse tube will cause thefuse tube to vent itself at the top as well as at the bottom and willblow the button head I8 directly upwardy from between the spring arms 51without damage to any portion of the upper stationary terminal, it beingnoted that the fuse tube opens directly outwardly through its upperterminal 20.

Thus the device is able to handle larger overloads than where apermanently closed upper end is provided. In addition to this, after thecircuit has been cleared within the fuse tube, the fuse tube is releasedas described and drops downwardly and outwardly to inoperative position.

In the form of the invention shown in Figures 4 and 5 the spring contactarms are indicated by the reference character 24 and have the downwardlyand outwardly slanting portions 24' which engage the button head I8 ofthe fuse link. These spring arms 24 are longer than the spring armsshown in the first form of the invention and may be clamped directlyagainst the upper end of the elongated insulator I, the bolt 25 alsosecuring the connector 26 in place. If desired, a rivet 21 may be passedthrough the base of the connector 26 and the spring arms. It ispreferable to pro- Vide a. rivet 28 intermediate the ends of the arms24. This rivet prevents spreading of the arms and additionally forms abearing against which the latching spring 29 is adapted to press, suchlatching spring having its rear portion downwardly turned as indicatedat 30 and clamped in place by means of the bolt 25. -The latching spring29 may have a tapered forward end as shown most clearly in Figure 5 andis provided with a rounded, downwardly projecting, rolled portion 3|.The portion 3| is adapted to latch in front of an upwardly protrudingpart 32 formed integrally with the upper terminal 33 of the fuse tube34. The rear face of the protuberance 32 is downwardly slanted toprovide a cam face 35 upon which the rounded portion 3| is adapted toride when the fuse tube is rocked into closed position. The uppercontact 33 of the fuse tube is provided with a manipulating eyeletportion 36.

The arms 24 are resilient as well as the spring 29 and the arms 24firmly grip the marginal edges of the button head IBof the fuse link andsecure a firm electrical contact therewith. They also urge the buttonhead I8 downwardly into firm engagement with the upper face of thereduced neck 31 of the upper contact 33 of the fuse tube. The latchingspring 29 also forms a. firm electrical contact with the terminal 33though the arms 24 are intended to carry the major part of the currentas in the form previously described.

Upon rupture of the fuse link, the button head is held down, thusclosing the upper end of the fuse tube on light overloads so that astraight expulsion action occurs. Thereafter the fuse tube dropsdownwardly and outwardly to ino erative position as previouslydescribed. However, on heavy overloads the button head is blown off fromthe fuse tube and freely passes from the spring arms 24, expanding thearms and traveling outwardly without damage to any portion of the upperstationary contact structure.

It will be seen that a novel form of fuse construction has been providedin which a larger overload can be handled than if the upper end of thefuse tube were closed. It will also be seen that under small overloads afull expulsion action occurs, whereas under heavy overoads the fuse tubeis vented both at its upper and at its lower end, thus avoidingexcessive pressures and enabling the device to handle relatively largeoverloads with safety.

It will be seen further that direct engagement is made between the uppercontact and the button head of the fuse link and that this electricalcontact between the button head and the upper stationary contact iseffective in providing a direct current path from the fuse link to theupper stationary contact.

It will also be seen that the construction is such that fuse links withdifferent sized button heads could be employed as the resiliency of thearms 24 is such that they will spread sufficiently to take larger sizedbutton heads as required.

Although this invention has been described in considerable detail, it isto be understood that such description is intended as illustrativerather than limiting, as the invention may be variously embodied and isto be interpreted as claimed.

We claim:

1. In a fuse construction, stationary terminals, a fuse tube open atboth ends and having a terminal at one end, and a fuse link having ahead normally closing one end of the fuse tube and extending throughsaid fuse tube and electrically connecting the stationary terminals, oneof said stationary terminals having a pair of downwardly divergentyielding members bearing on opposite sides of the head of said fuselink, whereby the head of the fuse link may be blown. outwardly betweenthe said yielding members upon rupture of the fuse link on heavyoverload.

2. In a fuse construction, stationary terminals,

7 a fuse tube open at both ends and having a terminal at one end, and afuse link having a head normally closing one end of the fuse tube andextending through said fuse tube and electrically connecting thestationary terminals, one of said stationary terminals having a pair ofdownwardly divergent yielding, flat, outwardly extending members bearingon opposite sides of the head of said fuse link, whereby the head of thefuse link may be blown outwardly between the said yielding members uponrupture of the fuse link on heavy overload.

3. In a fuse construction, stationary terminals, a fuse tube open atbothends and having a terminal at one end, and a fuse link having a headnormally closing one end of the fuse tube and extending through saidfuse tube and electrically connecting the stationary terminals, one ofsaid stationary terminals having a pair of downwardly divergent yieldingmembers bearing on opposite sides of the head of said fuse link, wherebythe head of the fuse link may be blown outwardly between the saidyielding members upon rupture of the fuse link on heavy overload, said Iyielding members holding the head of the fuse link in tube closedposition under light overloads.

4. In a drop-out fuse construction, an upper and a lower stationaryterminal, a fuse tube open at both ends and having a terminal at itsupper end and normally latched to the upper stationary terminal, a fuselink provided with a head at its upper end closing the upper end of saidfuse tube and extending downwardly through said fuse tube, meansadjacent the lower end of said fuse tube controlled by said fuse linkforreleasing said fuse tube upon rupture of said fuse link to allow saidfuse tube to drop downwardly and outwardly to inoperative position, saidupper terminal having a pair of spring arms projecting outwardlytherefrom engaging opposite sides of the head of said fuse link, saidpair of spring arms being sufficiently flexible to allow the passage ofthe head of the fuse link therebetween upon heavy overloads.

5. In a drop-out fuse construction, an upper and a lower stationaryterminal, a fuse tube open at both ends and having a terminal at itsupper end and normally latched to the upper stationary terminal, a fuselink provided with a head at its upper end closing the upper end ofsaidfuse tube and extending downwardly through said fuse tube, meansadjacent the lower end of said fuse tube controlled by said fuse linkfor releasing said fuse tube upon rupture of said fuse link to allowsaid fuse tube to drop downwardly and outwardly to inoperative position,said upper terminal having a pair of flat spring arms ongaging oppositesides of the head of the fuse link.

6. In a drop-out fuse construction, an upper and a lower stationaryterminal, a fuse tube open at both ends and having a terminal at itsupper end and normally latched to the upper stationary terminal, a fuselink provided with a head at its upper end closing the upper end of saidfuse tube and extending downwardly through said fuse tube, meansadjacent the lower end of said fuse tube controlled by said fuse linkfor releasing said fuse tube upon rupture of said fuse link to allowsaid fuse tube to drop downwardly and outwardly to inoperative position,said upper terminal having a. pair of flat, downwardly diverging springarms eng ging opposite sides of the head of the fuse link and urging thehead of the fuse link downwardly to tube closed position.

7. A fuse construction comprising an upper and a lower stationaryterminal, a fuse tube pivotally supported from the lower stationaryterminal and adapted to be rocked upwardly into latching engagement withthe upper stationary terminal,

said upper stationary terminal having latching means cooperating withsaid fuse tube, said fuse tube having a reduced neck portion, said upperstationary terminal having a pair of flat contact arms positioned onopposite sides of said neck portion, and a fuse link provided with ahead normally resting upon said neck portion and engaged by the saidflat arms of the upper stationary terminal, said fuse link extendingdownwardly through said fuse tube and being electrically connected tothe lower stationary terminal.

8. A fuse construction comprising an upper and a lower stationaryterminal, a fuse tube pivotally supported from the lower stationaryterminal and having an upper terminal, the upper stationary terminalhaving a pair of spaced spring arms adapted to engage the upper terminalof said fuse tube, to normally hold said fuse tube in operativeposition, said fuse tube being open at both ends, a fuse link having ahead normallyclosing the upper end of said fuse tube and extendingthrough said fuse tube and electrically connected to the lowerstationary terminal, means controlled by said fuse link adjacent thelower end of said fuse tube for releasing said fuse tube upon rupture ofsaid fuse link for outward and downward motion to inoperative positionwith the upper terminal of said fuse tube out of engagement with saidpair of spring arms, said upper stationary ter- Jecting outwardlytherefrom and engaging the head of said fuse link on opposite sidesthereof, said second pair of spring arms being located above the firstmentioned pair of spring arms of said upper stationary terminal.

9. A fuse construction comprising a pair of stationary terminals, a fusetube having a terminal at one end provided with a reduced tubular neckportion, said fuse tube being open at both ends, a fuse link having ahead normally closing one end of said fuse tube and resting against theend of the tubular neck of the terminal of said fuse tube and extendingthrough said fuse tube and electrically connected to one of saidstationary terminals, the other of said stationary terminals having apair of outwardly projecting spring arms out of contact with the neckportion of said upper terminal and engaging opposite sides of the headof said fuse link.

10. In a drop-out fuse construction, an upper and a lower stationaryterminal, a fuse tube pivotally supported from the lower stationaryterminal and open at both ends, said fuse tube having a terminal at itsupper end provided with a latching portion, said upper stationaryterminal having adownwardly urged spring arm provided with latchingmeans for cooperation with the latching portion of the terminal of saidfuse tube, a fuse link extending through said fuse tube and electricallyconnected to the lower stationary terminal and having a head normallyclosing the upper end of said fuse tube, said upper stationary terminalhaving a pair of downwardly divergent spring arms normally engagingopposite sides of the head of said fuse link and adapted to deflect andallow the head of the fuse link to pass therebetween on heavy overload,and means controlled by said fuse link adjacent the lower end of saidfuse tube, said means releasing said fuse tube upon rupture of said fuselink for outward and downward motion to inoperative position.

ROLLAND D. NELSON. EDWIN A. LINK.

